The present disclosure relates in general to indoor wayfinding systems for the blind, visually impaired, and disoriented, and, more specifically, to optimizing placement of Bluetooth Low Energy (BLE) beacons within a site or building with efficient use of time and effort.
Traditionally there have been few options for navigational aids for the blind and visually impaired (BVI) in large in-door spaces. Some recent indoor navigation systems allow users equipped with smartphones to interact with low cost Bluetooth-based beacons deployed strategically within the indoor space of interest to navigate their surroundings. A major challenge in deploying such beacon-based navigation systems is the need to employ a time and labor-expensive beacon deployment process to manually identify potential beacon placement locations and arrive at a topological structure representing the indoor space.
Way finding can be defined as knowing where you are in a building or an environment, knowing where your desired location is, and knowing how to get there from your present location. For outdoor environments, recent advances in global positioning systems (GPS) and mapping technologies provide accurate and simple to use means for way finding. For indoor environments, reading and following signs remains the easiest and most reliable option because GPS and associated advances for outdoor environments typically do not apply. This has, however, meant that indoor way finding has remained a challenge for the blind and visually impaired (BVI) in our society. Indoor environments can be geographically large and intimidating such as grocery stores, airports, sports stadiums, large office buildings, and hotels. A solution to the indoor way finding problem for the BVI also has broad applications for the sighted population. In unfamiliar, large indoor spaces, it is common for sighted people to be disoriented and have trouble finding their way around. This could be due to the lack of well marked signs and maps, or not being familiar with the conventions or language used on these signage, or just the fact that the layout of the space is disorienting.
One of the key building blocks of indoor way finding is knowing where a user is at all times in an indoor space. The challenge of indoor localization has been addressed by utilizing existing infrastructure or by adding additional infrastructure. The direction of using existing infrastructure in indoor spaces recently has largely revolved around using Wi-Fi access points (APs) that are already present. Under various assumptions, prior work has shown accuracies within a few meters. Although this direction achieves indoor way finding without any additional infrastructure costs, and allows users to use mobile devices they carry, the assumptions made have many limitations in achieving indoor way finding for the BVI. Most of these Wi-Fi based localization schemes require a very high density of Wi-Fi access points (three or more detectable at all times from the point of localization) to be accurate and useful. Furthermore, most of these schemes require additional hardware at the receiving device and/or APs and software mechanisms to be implemented at APs to assist with localization. Some of the proposed schemes also have the disadvantage that they require users to make certain device movements (such as rotating their device) for achieving accurate localization. This can be difficult for BVI users to do, especially those who already are using a cane or dog and will probably be mounting their smartphone in a pocket or strapping it onto themselves or an accessory.
Indoor way finding for the BVI does not require knowing the user's location at all times. Rather, it is more important to identify strategic points within an indoor space that a user should be localized at accurately (e.g., within 1-2 m localization error).
The approach of adding additional infrastructure in indoor spaces for localization has been explored in literature, primarily because of the potential of higher accuracies (compared to Wi-Fi based systems for example). Such work has included the use of technologies such as RFID, Ultra-Wideband (UWB), Ultrasound, Infrared (IR), and visible light. Many of these technologies (some specific to indoor way finding for BVI) are not effective for way finding indoors (and have rarely been used) because of the requirement of carrying additional hardware on the user, or more expensive or power-inefficient reference beacons in the environment. There have also been many attempts in the field of computer vision to assist with way finding for the blind and visually impaired. However, these tend to have high inaccuracies in the information read out when a user is mobile and text is not directly facing the user.
The most accurate and usable indoor way finding systems available to persons with low vision have relied on the use of radio frequency identification (RFID) tag technology. This solution, however, is not very flexible when it comes to changing embedded information on tags. Furthermore, the tag reader technology is expensive and can be difficult to integrate into current mobile systems. Other mechanisms that provide audible directions (e.g., Talking Signs® available from Talking Signs Services, Inc.) still need each user to possess special audio frequency devices capable of acting as receivers. In general, most approaches to solve this challenge require special hardware to be carried by the user. Such limitations have created barriers for widespread use and adoption for indoor way finding.
Systems have been disclosed (e.g., GuideBeacon and StaNavi) for way finding in large spaces using BLE beacons. For example, GuideBeacon discloses a smartphone-based system using a proximity detection algorithm to localize users and to provide walking directions as turn-by-turn instructions. The Wayfindr project is an effort to develop an open standard for navigation for the visually impaired in outdoor and indoor spaces, including the use of BLE beacons.
Thus, Bluetooth-based indoor localization is known. In particular, the introduction of Bluetooth Low Energy (BLE) provides improved localization over WiFi systems (e.g., accuracies as small as 0.53 m). Beacons are being deployed for interaction with smartphone apps to provide real-time location specific information using standardized protocols such as iBeacon from Apple and Eddystone from Google. All these recent trends in using BLE-beacons for localization indicate that the premise of using beacons for strategic localization is well-founded. By utilizing the increasing beacon deployments in indoor spaces, the infrastructure costs with beacon-based navigational systems are likely to be lower than with a system that is specifically designed only to be used for the BVI.
One major challenge facing beacon-based indoor way finding is that of creating fast and accurate representations of indoor spaces that can be used for beacon-placement and subsequent navigation computations. Manual determination of beacon placement locations and path computations is time-consuming and labor-expensive, especially for large indoor spaces. Such an approach requires the manual identification of walking paths on a floor plan, marking of points of interest, determining the distance between any two points of interest, determining the orientation between them for navigation, identifying shortest paths between points of interests, and subsequent adjustments to optimize the resulting paths that may require further iterations of the entire process. Another approach has been the use of mobile robots that can traverse an indoor space gathering information about walking paths within a space and allowing offline analysis of the gathered data to arrive at beacon placement locations and path computations for the space. This approach though not as labor-intensive as the manual process, is still time-consuming and requires expensive mobile robot hardware and software resources calibrated to work within each indoor space of interest. Crowdsourcing using people moving around the spaces that need to be mapped can be an effective way to create high quality maps inexpensively. However, this approach may not capture all areas of indoor spaces and the design and application of appropriate incentive mechanisms remains a challenge.
In summary, potential systems have been developed for BVI way finding using low-cost, stamp-size Bluetooth Low Energy (BLE) “beacon” devices embedded in the environment that interact with smartphones carried by users. Such beacon-based navigation systems have achieved promising preliminary results indicating that they may be a viable solution for indoor way finding for the BVI if some of the underlying challenges to the deployment of such systems can be overcome.